Network attached storage

Here's a little trivia. IBM created the first hard disk in 1956.
Called the RAMAC (Random Access Method of Accounting and Control), it
required 50 24-inch platters and held an amazing 5MB of data. You can
probably remember being the envy of the neighborhood when that pricey
new PC with the 100MB drive arrived. This brief look at the past shows
that data storage requirements increase as technology permits
individuals and companies to apply that power to creative and
cost-saving ends.

Networks share a common problem - where will the data be stored? On
small networks with a few users, most data is stored on the hard drives
contained within the network server or the workstation. In the
traditional model, shared data resides on the drive(s) of the
server(s), while applications and programs were loaded on the
workstation drive. The growth of centralized data storage is climbing
at a rapid pace due to several factors.

Increased numbers of users connected to the network.

Networks being used to archive data. This data is generally never
removed intentionally and therefore grows on a daily basis.

Increased need to access repositories of centralized data, such as
database, graphical and text-based information. In the case of
broadcast facilities, this would also include digitized audio and video
content.

Secure e-mail servers, such as Microsoft Exchange, storing and
archiving e-mail for all users connected to the network. The storage
requirements for e-mail accounts for the largest daily consumer use of
drive space in most networks.

Last month I discussed a method for increasing data storage capacity
that is currently being implemented by large- and medium-sized
businesses, the Storage Area Network (SAN.) Although SANs
represent the high-end of the network-storage spectrum, they can still
be expensive for most network operators. This month we will look at
network storage for the rest of us. Network Attached Storage
(NAS) is a more realistic, albeit less sophisticated option to increase
storage across a network.

systems range in sizes from 40GB to nearly
1TB. Photo courtesy of Dell.

NAS devices are simply stand-alone servers that only provide storage
for data over a network. In practice, these are typically
“plug-and-play” devices that can be attached directly to
the network; some refer to NAS devices as “network
appliances.” These devices can be simple stand-alone units or
frames housing “drive-clusters” or multiple disk
arrays.

NAS features

When it comes to increasing the available storage space across a
network, NAS devices provide the simplest and most cost-effective
means. NAS has several advantages. It is low cost and easy to deploy,
maintain and operate. The low cost also applies to a low total cost of
ownership (TCO). From a performance standpoint, NAS yields high
performance, is scalable, widely available and will work across
multiple platforms, such as Windows NT and Unix.

The cost of NAS devices has decreased a great deal over the past two
years. For instance, prices for a 20GB Quantum Snap Server start at
about $500 with models available that will provide up to 900GB of
storage. Several other manufacturers sell similar canned and custom NAS
products that offer a variety of storage, format and performance
options. The total cost of ownership for NAS devices is also relatively
low due to the reduced time necessary for installation, network
downtime and regular maintenance. (See Table 1.)

NAS devices can be added easily to any existing network platform
within minutes, generally without causing any disruption or requiring
network shutdown. NAS is inherently scalable: as storage requirements
increase; simply add an additional device or, in the case of NAS drive
clusters, an additional drive.

Protect any storage device that holds mission-critical data against
catastrophic failure. Similar to features found in network servers, NAS
devices, except with the most inexpensive units, permit the
configuration of hard drives to work as a RAID (Redundant Arrays of
Independent Disks), which can prevent data loss in the event of a
single drive failure. Different levels of RAID provide six levels of
protection utilizing specific methods that ensure the integrity/access
speed of data. For instance, RAID level 1 simply duplicates data from a
primary drive on a secondary drive, where RAID level 5 distributes data
across all drives within an array. The cost to achieve these levels of
protection ranges from minimal to rather expensive depending on the
specific approach.

The key benefit of utilizing NAS is an increase in overall
performance of your network. On network backbones that handle moderate
to heavy traffic, NAS systems will improve the speed of the network.
NAS separates file sharing from application sharing, which frees the
network server from the additional overhead formally used to manage
data files. The net effect is an increase in available network server
bandwidth resulting in faster processing.

NAS can be configured to appear as a native file server for multiple
network operating system platforms. For example, if your company
utilizes a mix of operating system platforms, such as Windows NT and
Linux, files will be saved and retrieved in their native file format,
thus eliminating the need to convert a business to a single network
platform. That flexibility can relieve you from having to upgrade or
change existing hardware.

While NAS and SAN both permit the efficient storage of data, they
are very different in terms of implementation, deployment and cost.
Remember that the SAN is a separate network that requires an
independent high-speed backbone, such as Fibre Channel. SANs also move
and store data as “blocks.” The cost to build a SAN is
significant not only in terms of the hardware and software, but also
the level of expertise and manpower required for ongoing maintenance,
etc. In contrast, NAS simply attaches to an existing Ethernet backbone
and transfers data as "files." NAS devices can be installed and
configured with minimal difficulty and the cost is within the budget of
most broadcasters.

Storage

Cost

Installation
($50/hour)

Network Downtime
($500/hour)

Maintenance
($50/hour)

3-year
TCO

160GB Snap Server 2200

$1,499

0.25 hours, $15

0.25 hours, $125

0.5 hours/mo, $25

$2,539

160GB 2000/NT Server

$6,842

4 hours, $200

4 hours, $2,000

4 hours/mo, $200

$16,242

400GB Snap Server 4100

$4,799

0.5 hours, $25

0.5 hours, $250

0.5 hours/mo, $25

$5,974

300GB 2000/NT Server

$9,158

4 hours, $200

4 hours, $2,000

4 hours/mo, $200

$18,558

960GB Snap Server 12000

$14,999

0.5 hours, $25

0.5 hours, $250

0.5 hours/mo, $25

$15,174

900GB 2000/NT Server W/disk Array

$25,633

4 hours, $200

4 hours, $2,000

4 hours/mo, $200

$35,033

Table 1. Total cost of ownership for various
storage methods. Data courtesy of Quantum Corp.

Kevin McNamara, BE Radio's consultant on computer technology, is
president of Applied Wireless Inc., New Market, MD.

All of the Networks articles have been approved by the SBE
Certification Committee as suitable study material that may assist your
preparation for the SBE Certified Broadcast Networking Technologist
exam. Contact the SBE at (317) 846-9000 or go to